Field of the Invention
The present invention relates to a technique of correcting the blur of an image to be captured by using a plurality of correction optical systems.
Description of the Related Art
Recently, an image stabilization function, which not only corrects the blur of an image to be captured caused by camera shake while the user is standing still but also corrects a relatively large blur caused when the user performs shooting with one hand and the large blur of an image to be captured caused when the user performs shooting while walking, has become widespread.
Image stabilization methods include techniques such as an optical image stabilization technique of shifting an optical axis in accordance with blur by optically moving a correction lens and an electronic image stabilization technique of changing a cutout region output from an image captured by an image sensor in accordance with blur.
In order to correct a large blur, an optical image stabilization scheme needs to increase a correction angle, whereas an electronic image stabilization scheme needs to set a large surplus pixel region. Either method needs to expand a correction range. When expanding a correction range, however, the optical image stabilization scheme suffers from a problem that a lens or actuator increases in size or the optical performance deteriorates when the lens is greatly shaken. In addition, the electronic image stabilization scheme suffers from a problem that a reduction in effective region leads to a deterioration in image quality and an increase in the size of an image sensor leads to an increase in power consumption.
In order to solve such problems, Japanese Patent Laid-Open No. 2003-202499 has proposed a method of providing and driving two correction optical systems for image stabilization. In addition, Japanese Patent Laid-Open No. 2010-4370 has proposed a method which provides a correction optical system and an electronic correction system and corrects blur by separating it into a high frequency band and a low frequency band and performing correction for each frequency band using two correction systems.
The technique disclosed in Japanese Patent Laid-Open No. 2010-4370, however, gives no consideration to the movement of camerawork such as panning at the time of moving image shooting. For this reason, the following problem arises.
That is, when the two correction systems are always controlled after the separation of blur into a high frequency component and a low frequency component at the time of a camera operation such as panning, a blur correction residue remains. This is because when panning is detected, an end of correction is reached unless correction on the lower frequency side is inhibited. Upon detection of panning, therefore, it is necessary to change a correction control method so as to inhibit correction. If, however, panning is detected and correction is inhibited while a high frequency component and a low frequency component are separated from each other, a high frequency component is also not corrected. As a result, high frequency blur remains.